1 // SPDX-License-Identifier: GPL-2.0-only <<
2 /* Copyright (C) 2010: YOSHIFUJI Hideaki <yosh 1 /* Copyright (C) 2010: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
3 * Copyright (C) 2015: Linus Lüssing <linus.l 2 * Copyright (C) 2015: Linus Lüssing <linus.luessing@c0d3.blue>
4 * 3 *
>> 4 * This program is free software; you can redistribute it and/or
>> 5 * modify it under the terms of version 2 of the GNU General Public
>> 6 * License as published by the Free Software Foundation.
>> 7 *
>> 8 * This program is distributed in the hope that it will be useful, but
>> 9 * WITHOUT ANY WARRANTY; without even the implied warranty of
>> 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>> 11 * General Public License for more details.
>> 12 *
>> 13 * You should have received a copy of the GNU General Public License
>> 14 * along with this program; if not, see <http://www.gnu.org/licenses/>.
>> 15 *
>> 16 *
5 * Based on the MLD support added to br_multic 17 * Based on the MLD support added to br_multicast.c by YOSHIFUJI Hideaki.
6 */ 18 */
7 19
8 #include <linux/skbuff.h> 20 #include <linux/skbuff.h>
9 #include <net/ipv6.h> 21 #include <net/ipv6.h>
10 #include <net/mld.h> 22 #include <net/mld.h>
11 #include <net/addrconf.h> 23 #include <net/addrconf.h>
12 #include <net/ip6_checksum.h> 24 #include <net/ip6_checksum.h>
13 25
14 static int ipv6_mc_check_ip6hdr(struct sk_buff 26 static int ipv6_mc_check_ip6hdr(struct sk_buff *skb)
15 { 27 {
16 const struct ipv6hdr *ip6h; 28 const struct ipv6hdr *ip6h;
17 unsigned int len; 29 unsigned int len;
18 unsigned int offset = skb_network_offs 30 unsigned int offset = skb_network_offset(skb) + sizeof(*ip6h);
19 31
20 if (!pskb_may_pull(skb, offset)) 32 if (!pskb_may_pull(skb, offset))
21 return -EINVAL; 33 return -EINVAL;
22 34
23 ip6h = ipv6_hdr(skb); 35 ip6h = ipv6_hdr(skb);
24 36
25 if (ip6h->version != 6) 37 if (ip6h->version != 6)
26 return -EINVAL; 38 return -EINVAL;
27 39
28 len = offset + ntohs(ip6h->payload_len 40 len = offset + ntohs(ip6h->payload_len);
29 if (skb->len < len || len <= offset) 41 if (skb->len < len || len <= offset)
30 return -EINVAL; 42 return -EINVAL;
31 43
32 skb_set_transport_header(skb, offset); 44 skb_set_transport_header(skb, offset);
33 45
34 return 0; 46 return 0;
35 } 47 }
36 48
37 static int ipv6_mc_check_exthdrs(struct sk_buf 49 static int ipv6_mc_check_exthdrs(struct sk_buff *skb)
38 { 50 {
39 const struct ipv6hdr *ip6h; 51 const struct ipv6hdr *ip6h;
40 int offset; 52 int offset;
41 u8 nexthdr; 53 u8 nexthdr;
42 __be16 frag_off; 54 __be16 frag_off;
43 55
44 ip6h = ipv6_hdr(skb); 56 ip6h = ipv6_hdr(skb);
45 57
46 if (ip6h->nexthdr != IPPROTO_HOPOPTS) 58 if (ip6h->nexthdr != IPPROTO_HOPOPTS)
47 return -ENOMSG; 59 return -ENOMSG;
48 60
49 nexthdr = ip6h->nexthdr; 61 nexthdr = ip6h->nexthdr;
50 offset = skb_network_offset(skb) + siz 62 offset = skb_network_offset(skb) + sizeof(*ip6h);
51 offset = ipv6_skip_exthdr(skb, offset, 63 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
52 64
53 if (offset < 0) 65 if (offset < 0)
54 return -EINVAL; 66 return -EINVAL;
55 67
56 if (nexthdr != IPPROTO_ICMPV6) 68 if (nexthdr != IPPROTO_ICMPV6)
57 return -ENOMSG; 69 return -ENOMSG;
58 70
59 skb_set_transport_header(skb, offset); 71 skb_set_transport_header(skb, offset);
60 72
61 return 0; 73 return 0;
62 } 74 }
63 75
64 static int ipv6_mc_check_mld_reportv2(struct s 76 static int ipv6_mc_check_mld_reportv2(struct sk_buff *skb)
65 { 77 {
66 unsigned int len = skb_transport_offse 78 unsigned int len = skb_transport_offset(skb);
67 79
68 len += sizeof(struct mld2_report); 80 len += sizeof(struct mld2_report);
69 81
70 return ipv6_mc_may_pull(skb, len) ? 0 82 return ipv6_mc_may_pull(skb, len) ? 0 : -EINVAL;
71 } 83 }
72 84
73 static int ipv6_mc_check_mld_query(struct sk_b 85 static int ipv6_mc_check_mld_query(struct sk_buff *skb)
74 { 86 {
75 unsigned int transport_len = ipv6_tran 87 unsigned int transport_len = ipv6_transport_len(skb);
76 struct mld_msg *mld; 88 struct mld_msg *mld;
77 unsigned int len; 89 unsigned int len;
78 90
79 /* RFC2710+RFC3810 (MLDv1+MLDv2) requi 91 /* RFC2710+RFC3810 (MLDv1+MLDv2) require link-local source addresses */
80 if (!(ipv6_addr_type(&ipv6_hdr(skb)->s 92 if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL))
81 return -EINVAL; 93 return -EINVAL;
82 94
83 /* MLDv1? */ 95 /* MLDv1? */
84 if (transport_len != sizeof(struct mld 96 if (transport_len != sizeof(struct mld_msg)) {
85 /* or MLDv2? */ 97 /* or MLDv2? */
86 if (transport_len < sizeof(str 98 if (transport_len < sizeof(struct mld2_query))
87 return -EINVAL; 99 return -EINVAL;
88 100
89 len = skb_transport_offset(skb 101 len = skb_transport_offset(skb) + sizeof(struct mld2_query);
90 if (!ipv6_mc_may_pull(skb, len 102 if (!ipv6_mc_may_pull(skb, len))
91 return -EINVAL; 103 return -EINVAL;
92 } 104 }
93 105
94 mld = (struct mld_msg *)skb_transport_ 106 mld = (struct mld_msg *)skb_transport_header(skb);
95 107
96 /* RFC2710+RFC3810 (MLDv1+MLDv2) requi 108 /* RFC2710+RFC3810 (MLDv1+MLDv2) require the multicast link layer
97 * all-nodes destination address (ff02 109 * all-nodes destination address (ff02::1) for general queries
98 */ 110 */
99 if (ipv6_addr_any(&mld->mld_mca) && 111 if (ipv6_addr_any(&mld->mld_mca) &&
100 !ipv6_addr_is_ll_all_nodes(&ipv6_h 112 !ipv6_addr_is_ll_all_nodes(&ipv6_hdr(skb)->daddr))
101 return -EINVAL; 113 return -EINVAL;
102 114
103 return 0; 115 return 0;
104 } 116 }
105 117
106 static int ipv6_mc_check_mld_msg(struct sk_buf 118 static int ipv6_mc_check_mld_msg(struct sk_buff *skb)
107 { 119 {
108 unsigned int len = skb_transport_offse 120 unsigned int len = skb_transport_offset(skb) + sizeof(struct mld_msg);
109 struct mld_msg *mld; 121 struct mld_msg *mld;
110 122
111 if (!ipv6_mc_may_pull(skb, len)) 123 if (!ipv6_mc_may_pull(skb, len))
112 return -ENODATA; !! 124 return -EINVAL;
113 125
114 mld = (struct mld_msg *)skb_transport_ 126 mld = (struct mld_msg *)skb_transport_header(skb);
115 127
116 switch (mld->mld_type) { 128 switch (mld->mld_type) {
117 case ICMPV6_MGM_REDUCTION: 129 case ICMPV6_MGM_REDUCTION:
118 case ICMPV6_MGM_REPORT: 130 case ICMPV6_MGM_REPORT:
119 return 0; 131 return 0;
120 case ICMPV6_MLD2_REPORT: 132 case ICMPV6_MLD2_REPORT:
121 return ipv6_mc_check_mld_repor 133 return ipv6_mc_check_mld_reportv2(skb);
122 case ICMPV6_MGM_QUERY: 134 case ICMPV6_MGM_QUERY:
123 return ipv6_mc_check_mld_query 135 return ipv6_mc_check_mld_query(skb);
124 default: 136 default:
125 return -ENODATA; !! 137 return -ENOMSG;
126 } 138 }
127 } 139 }
128 140
129 static inline __sum16 ipv6_mc_validate_checksu 141 static inline __sum16 ipv6_mc_validate_checksum(struct sk_buff *skb)
130 { 142 {
131 return skb_checksum_validate(skb, IPPR 143 return skb_checksum_validate(skb, IPPROTO_ICMPV6, ip6_compute_pseudo);
132 } 144 }
133 145
134 static int ipv6_mc_check_icmpv6(struct sk_buff !! 146 int ipv6_mc_check_icmpv6(struct sk_buff *skb)
135 { 147 {
136 unsigned int len = skb_transport_offse 148 unsigned int len = skb_transport_offset(skb) + sizeof(struct icmp6hdr);
137 unsigned int transport_len = ipv6_tran 149 unsigned int transport_len = ipv6_transport_len(skb);
138 struct sk_buff *skb_chk; 150 struct sk_buff *skb_chk;
139 151
140 if (!ipv6_mc_may_pull(skb, len)) 152 if (!ipv6_mc_may_pull(skb, len))
141 return -EINVAL; 153 return -EINVAL;
142 154
143 skb_chk = skb_checksum_trimmed(skb, tr 155 skb_chk = skb_checksum_trimmed(skb, transport_len,
144 ipv6_mc 156 ipv6_mc_validate_checksum);
145 if (!skb_chk) 157 if (!skb_chk)
146 return -EINVAL; 158 return -EINVAL;
147 159
148 if (skb_chk != skb) 160 if (skb_chk != skb)
149 kfree_skb(skb_chk); 161 kfree_skb(skb_chk);
150 162
151 return 0; 163 return 0;
152 } 164 }
>> 165 EXPORT_SYMBOL(ipv6_mc_check_icmpv6);
153 166
154 /** 167 /**
155 * ipv6_mc_check_mld - checks whether this is 168 * ipv6_mc_check_mld - checks whether this is a sane MLD packet
156 * @skb: the skb to validate 169 * @skb: the skb to validate
157 * 170 *
158 * Checks whether an IPv6 packet is a valid ML 171 * Checks whether an IPv6 packet is a valid MLD packet. If so sets
159 * skb transport header accordingly and return 172 * skb transport header accordingly and returns zero.
160 * 173 *
161 * -EINVAL: A broken packet was detected, i.e. 174 * -EINVAL: A broken packet was detected, i.e. it violates some internet
162 * standard 175 * standard
163 * -ENOMSG: IP header validation succeeded but !! 176 * -ENOMSG: IP header validation succeeded but it is not an MLD packet.
164 * with a hop-by-hop option. <<
165 * -ENODATA: IP+ICMPv6 header with hop-by-hop <<
166 * but it is not an MLD packet. <<
167 * -ENOMEM: A memory allocation failure happen 177 * -ENOMEM: A memory allocation failure happened.
168 * 178 *
169 * Caller needs to set the skb network header 179 * Caller needs to set the skb network header and free any returned skb if it
170 * differs from the provided skb. 180 * differs from the provided skb.
171 */ 181 */
172 int ipv6_mc_check_mld(struct sk_buff *skb) 182 int ipv6_mc_check_mld(struct sk_buff *skb)
173 { 183 {
174 int ret; 184 int ret;
175 185
176 ret = ipv6_mc_check_ip6hdr(skb); 186 ret = ipv6_mc_check_ip6hdr(skb);
177 if (ret < 0) 187 if (ret < 0)
178 return ret; 188 return ret;
179 189
180 ret = ipv6_mc_check_exthdrs(skb); 190 ret = ipv6_mc_check_exthdrs(skb);
181 if (ret < 0) 191 if (ret < 0)
182 return ret; 192 return ret;
183 193
184 ret = ipv6_mc_check_icmpv6(skb); 194 ret = ipv6_mc_check_icmpv6(skb);
185 if (ret < 0) 195 if (ret < 0)
186 return ret; 196 return ret;
187 197
188 return ipv6_mc_check_mld_msg(skb); 198 return ipv6_mc_check_mld_msg(skb);
189 } 199 }
190 EXPORT_SYMBOL(ipv6_mc_check_mld); 200 EXPORT_SYMBOL(ipv6_mc_check_mld);
191 201
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